Method of protecting high-tension lines against flashovers



Nov. 13, 1928. 1,691,316 A. VAUPEL METHOD OF PROTECTING HIGH TENSION LINES AGAINST FLASHOVERS Filed Feb. 26, 1925 Fly.

Fly. 3. F1924.

1 INVENTOR 25% I filberl Vaupe/ TTO'R EY Patented j UNITED a 1 g 1 r 1,691,31 A E T "ALBERT vAurntQor BERLIN-GRUNEWALD, G R ASSIGNOR TO wns'rmonousn nmc'rmc & MANUFACTURING COMPANY, or NEW Yoax, n; Y., A coaroiwrron obtain therein.

zation takes place at the positive'conductor.

V secondary windings 1 and 2, respectively.

mmon or rao'rn'cmmo aIGH rENsIoiv LINES AGAIN-ST FLASHOVERS.

Application filed. February a, 1025, Serial No 11,899, and in'Gei-many February 27, 1924.

My invention relates to improvements in methods of, and apparatus for,'protect1ng high-tension distribution systems;

An object of my invention is to diminish the danger of flashover betweenthe line conductors of'a high-tension distribution system and ground .whenabnormal potentials It has been found when'the potential between two' rounded conductors is increased until a flashover occurs, that the initial ioni- If the positive conductor is provided with points or sharp'edges, a corona discharge takes'place but flashover does not occur until a higher potential difference isreached. It isfundesirable, however, t0 utilize the increased corona discharge to prevent flashover because oftheloss of energy'entailed where the conductors are of considerable length.--

According to my invention, the tendency to fiashover is minimized by reducing the maxiground 7 potential. This may be accom-.

plished either by transp'osing the axis of the alternating-current wave or by generating an alternating potential ofwhich the negative wave has a higher peakvalue than the positive wave. Fora better understanding of my invention, reference may be hacl ing drawing wherein a i Fig. 1 is a diagrammatic view of an elec-- trical system embodying my invention; 1

Fig. 2 is a graphillustrating the potential relations in the system shown in Fig. 1; a Fig. 3 is a diagrammatic view of the field structure of an alternatoradapted for carrying out the invention; and v i Fig. 4 is a graph illustrating wave produced by the alternator shown n f Referring to Fig. 1, an electrical distribution system is shown OOIIlPllSiIlg'll' step-up transformer having polyphase primary and The secondary windings 2 are connected in star relationto the conductors 3 of the higha tention transmission circuit.' The neutral point 5 of the secondary windings' 2 is connected'to the negative terminal of a directcurrent generator 9, the positive termlnal of the, generator being connected to ground. The neutral point is,,therefore, ata negative to the accompany-- carried out by the voltage potential with respect to ground so that the axis of the alternating potential of the conductors 3 is displaced as shown in Fig. 2 in such a manner that the amplitude of the posicrating a non-symmetrical potential. For

example, as 'indicatedin Fig. 3, the successive poles 10 of an alternator may be arranged to induce unequal potentials in the conductors (not shown) imbedded in a stator 11. This result may be accomplished by so shaping the pole tips 12 and 13 of the pole pieces that the magnetic circuit including the pole piece 12 has a greater reluctance than that including the pole piece 13. The alternating potential produced by a generator of this construction is shown iii-Fig. 4, the magnitude of the positive half-cycle of potential 14 being smaller than the magnitude of the negative half-cycle of potential 15.

While I have described several modificationsof my invention, by way of example, it 1 will be understood that the invention may be other means as will be obvious to those skilled in the art.

I claim as my invention: p

1. The method of protecting high-tension I electricalv distribution systems aganst flashover which consists in reducing the magnitude of the positive half-cycle of potential with respect to the magnitude of the'negative half-cycle of potential. a

2.An' alternating-current protective system comprising line conductors, and means for preventing linefiashover including a starconnected device; connected to said line conductors and a direct-current source of potential having its negative terminal connected tothe neutral of thestar-connected device and having its positive terminal connectedto ground. 1

3. The combination with an alternatingcurrent line, of means for preventing line flash over including means for reducing the magnitude of the positive half-cycle with rerespect to the magnitude of the negative halfspect to the magnitude of the negative half cycle of voltage, the last-named means includcycle of voltage. ing a substantially unloaded source of direct- 10 4:. The combination with an alternating current potential. o 1 I 5 current line, of means for preventing line In testimony whereof'laflix my signature. fiashover including means for reducing the magnitude of the positive half-cycle with i ALBERT VAUPEL; 

